From hanging out with movie stars to schmoozing with international royalty, Ted Leonsis enjoys a pretty glamorous lifestyle. Still, days spent on planes, film sets, galas and sports arenas present a special challenge for the Internet executive turned sport-team owner and filmmaker. That’s because Leonsis lives with life-threatening allergies to peanuts and tree nuts, not to mention environmental allergies and asthma.

Leonsis, who’s best known for owning the NHL’s Washington Capitals and the NBA’s Washington Wizards, spoke to Allergic Living’s Kim Shiffman and revealed a lot about balancing an on-the-go lifestyle with his severe allergies.

Exactly what are you allergic to?

I’m allergic to every nut imaginable, plus cats and dogs, dust, mold, all the pollens, trees and grass. I’ve got a litany.

When were you diagnosed?

When I was a baby, my mom knew something was wrong with me because of how I would react to some foods. It was hit or miss, and she just thought, “Boy, guess he didn’t like that.”

Then one day I went shopping with her at Christmas, and they were roasting nuts in the store. The steam was going up in the air, and as we were walking down the aisle, I went into anaphylactic shock. An ambulance came and they took me to hospital. My mother didn’t know what had happened, but the doctor asked a lot of questions, sent me for skin tests and that’s when they realized how much allergy I had.

What’s the worst allergic reaction you’ve had?

One I remember that was really, really bad happened when I was 9 or 10. I went to a sleepover at a friend’s summerhouse, and he had cats. It activated a really bad asthma attack; I couldn’t breathe and got a bad headache. They took me to the hospital.

But more recently, in 2006, I was producing a movie – Woody Harrelson was in it and a bunch of other movie stars. We were on a studio lot in L.A. and it was late at night, maybe 10:30 p.m. Because it had been such a successful shoot, the crew ordered chicken-salad sandwiches from some famous L.A. restaurant. This is what they always did to celebrate.

The sandwiches came, and I took one. After a couple of bites, I noticed something crunchy. It was cashews. Immediately I started to get hives on my hands, then my ears, then my tongue. And I thought, “Here it comes.”